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What are Cosmic Rays?A short historyWhat do we know now about CRsCR – their energy spectrum
Why all these is interesting?How CRs can be accelerated?Ultra High Energy and GZK Cut-OffVarious speculations
EAS detection from the SpaceEUSO, OWL, TUSUHECR simulation and reconstructionExpected Performance
Conclusions
UHECR detection from the Space
MunichMarch 2004
…by Dmitry Naumov(JINR)
What are Cosmic Rays?Cosmic Rays (CR) are high-energyparticles of extraterrestrial origin
The astrophysical filed of activityfor particle and nuclear physics
Secondary CR (produced by the primaries in the Earth’s atmosphere) consist of essentially allelementary particles and nulei (both stable and unstable). The most important are
• nucleons, nuclei & nucleides,• (hard) gammas,
• mesons (±,0,K±, …, D±,…),• charged leptons (e±, ±, ±),• neutrinos & antineutrinos (e, , ).
However the above definition is much wider and includes in fact all stable and quasistableparticles:
• neutrons,• antiprotons & (maybe) antinuclei,• hard gamma rays ( cm),• electrons & positrons,• neutrinos & antineutrinos,• esotheric particles (WIMPs,
magnetic monopoles, mini blackholes,...).
“Classical” CR are nuclei or ionized atomsranging from a single proton up to an ironnucleus and beyond, but being mostlyprotons (~90%) and particles (~9%).
Courtesy by V.Naumov
A gold-leaf Bennet-type electroscope(ca. 1880s) manufactured by Ducretet.
Even very well isolated gold-leaf electroscopes
are discharged at a slow rate.
… observed by scientists before 1900
J.Elster, H. F.Geitel, C.Wilson investigated this phenomenon and concluded that some unknown source of ionizing radiation existed. Wilson even surmised that the ionization might be
“…due to radiation from sources outside our atmosphere, possibly radiation like Röntgen rays or like cathode rays, but of enormously greater penetrating power.”
1900-1901
Soon after, two Canadian groups, Ernst Rutherford and H. Lester Cooke(1903) at McGill University, and J. C. McLennan and E. F. Burton (1902) at theUniversity of Toronto showed that 5 cm of lead reduced this mysterious radiationby 30%. An additional 5 t of pig lead failed to reduce the radiation further.
Courtesy by V.Naumov
1911–1913
Von Victor Franz Hess, studying at the Radium Inst.,Vienna, decided to take the experiment a step furtherand a few thousand meters higher. In 10 balloonascents (with open gondola) reaching altitudes of17,500 ft (about 5.3 km), he found that radiationslowly decreased with height (up to about 700 m) butthen at about 1.5 km it began to rise, until at 5 km itwas over twice the surface rate. Hess concluded :
"The results of the present observations seem to be most readily explained by the assumption that a radiation of very high penetrating power enters our atmosphere from above, and still produces in the lowest layers a part of the ionization observed in closed vessel."
Hess also found that the ionization was similar for day and nigh t time and did not decrease on his flight during a solar eclipse on April 12, 1912; he concluded the sun could not be the main source of the radiation.
Courtesy by V.Naumov
Victor Hess won The Nobel Prize in Physics 1936"for his discovery of cosmic radiation" .
Classic references:
• V.F. Hess, Physik. Zeitschr. 12 (1911) 998.• V.F. Hess, Physik. Zeitschr. 13 (1912) 1084.• V.F. Hess, Physik. Zeitschr. 14 (1913) 610.
Background of the slide:
H.E.S.S. (High Energy Stereoscopic System) a next-generation system of Imaging Atmospheric Cherenkov Telescopes for the investigation of cosmic gamma rays in the 100 GeV energy range.
Courtesy by V.Naumov
EAS
1938: Pierre Victor Auger, Raymond Maze, Roland Maze and Thérèse Grivet-Meyer positioned their particle detectors high in the Alps. They obtained that two detectors distanced many meters one from another detected the arrival of particles at exactly the same time.
Thus Pierre Auger and collaborators discovered the extensive air showers(EAS), the cascades of secondary particles and nuclei produced by the collision of primary high-energy particles with air molecules. In this way, changing the distance between detectors, Auger could observe particles with energies of about 1 PeV(1015 eV) - ten million times higher than reached so far. *)
________________________________________
*)Of course, this is the today’s estimaton. Auger was not able to estimate the primary energy. Courtesy by V.Naumov
Up to now EAS are detected on the Earth ground
Today the largest ground detector Pierre Auger in Argentina camps will cover ~3000 km2 surface and detect both:
Charged particlesFluorescent light
Courtesy by V.Naumov
1st knee
Foot (?)
Modulated by solar activity
1 particle per m2×second
1 particle per m2×year
2nd knee
Ankle
Fingers (?)
1 particle per km2×year
A Bird view of the CR spectrum
1st knee~ 3×106 GeV
GZK~ 5×1010 GeV
ankle~ 5×109 GeV
2nd knee~ 4×108 GeV
Courtesy by V.Naumov
A lower energy data suggests a dominance of the protons… •The AGASA data seems to conflict to both Hires and GZK prediction.•There is also a 2 times difference in the flux measurement between Hires and AGASA at low energies!
Hires is a fluorescent detectorAGASA is a charge track detector
A brief history of AGASA-HIRES conflict
NO
W
One if the HiRes cameras which has an exposure slightly greater then that of AGASA recorded only 2 events above 1020 eV compared to 20 expected if AGASA is right.
PAST
Also HiRes reported data from their stereo system (20% of their monocular exposure). They observed only 1 event with 1020.5 eV
Recently AGASA reported 17 events above 1020eV consistent with their previous work.
HiRes showed 7 events above 1020 eV in agreement with AGASA
Before 2001 event rate at 1019 eV reported by different experiments was in agreement at 10-15% level.
Haverah Park experiment (England) reassessed their energy spectrum
4 events above 1020 eV shifted by 30% below 1020 eV.
On top of that…
The arrival direction of UHECRs
There is a systematic enhancement of events with energy until 1019 eV correlated to the galactic plane
There is a deficit of events correlated to the galactic plane above 1019 eV
Haverah Park indicates a correlation with super-galactic plane (plane with Virgo radio galaxies cluster) above 4.1019 eV
However AGASA, SUGAR and Fly’s Eye do not confirm this result
Isotropic distribution of CR events with energy > 1019 eV observed (Takeda et al., 1999).
AGASA Super GZK event distribution.
Do UHECRs come from the same Source?
Probability of clusters at AGASA
Impressive chance probability howeverSignificantly depends on the binning.This is NOT a blind analysis
AGASA resolution
How UHECRs are accerelated?
1. Top down (TD, Big-Bang Remnants, WIMPs etc)
2. Bottom Up (shock waves, RadioGalaxies, etc)
3. Diffusion acceleration at Newtonian Shocks
4. Unipolar induction (rotating magnetic fields strong electric field)
5. Non-linear particle-wave interaction 6. Active Galactic Nuclei and Dead Quasars 7. Neutron Stars 8. Gamma Ray Bursts 9. etc… A lot of speculation but nobody knows (and
if knows does not tell us) the truth…
How UHECRs Propagate?
• 2.73°K cosmic microwave background (CMB)
• (GZK) Cutoff
eV
cmphotonsn
4
3
1035.6
413
eVENp
eVENp
NCMB
NCMB
20
20
105.2,
101.1,
Eth > 5.1019eV
Proton Propagation
• 2.73°K cosmic microwave background (CMB)
• (GZK) Cutoff
eV
cmphotonsn
4
3
1035.6
413
eVENp
eVENp
NCMB
NCMB
20
20
105.2,
101.1,
Greisen-Zatsepin-Kuzmin (GZK) CutOff
Eth > 5.1019eV
The mainmechanism
Heavy Nuclei Propagation
1. Compton interactions2. Pair production3. Photodisintegration4. Hadron
photoproduction
t[s]1014 1016
Photon Propagation
Energy loss is well understood as a pair creationTrough collisions with various radiation fields
How to avoid GZK?
Z0 burst from the annihilation with CNB relic neutrinos in Virgo Cluster. The decay products of Z0 are gamma rays, nucleons and neutrinos, as firmly established by the CERN LEP experiments.
Strong neutrino flux @ E>1021eV can propagate unattenuated and give us photons, nucleons and pions interacting with CNB!
Neutrino can propagate trougth CNB = (n)-
1~4 x 1028 cmAbove the size of the horizon (H0
-
1~1028cm)
Galactic Halo
Extra Galactic
SUSY U (uhecron)Good candidate is g~-hadron (gluino containing hadron): QCD sum rules suggests gluballino (gg~).
There are two narow allowed windows for g~-hadron mass:(1.5-3) GeV/c2 and (25-35) GeV/c2
1.5 GeV1 GeV2 GeV
Lorenz symmetry violationNo reason to believe for a universal scale below which
theLorenz symmetry is violated.However Local Lorenz Invariance could be violated
With anomalous kinematics
Without anomalous kinematics
Lorenz symmetry violationNo reason to believe for a universal scale below which
theLorenz symmetry is violated.However Local Lorenz Invariance could be violated
Could exist a maximum attainable velocity for each particle
ik = ci-ck difference in speeds4wpE + (m
2-mp2)/E energy
conservationIf p >4w2/ (m
2-mp2) = 3.5
10-25(w/w0)2
Has no solution no GZK limit
Lorenz symmetry violation
There are no direct constrains on the parameter p
However we can compare the speed of light to that oh highenergy CR which should emit the Cherenkov light if c < cCR Today constrains:p<3.0 10-23
e<1.3 10-13From CRs of highest energy
e<1.3 10-
15
<1.0 10-8
From Multi-TeV ray observationsFrom SN1987a
• Spectrum of energy
• Nature (p, Fe, , … )
• Sources
unknown!
• Unknown in addition :Is GZK limit is violated or no ?
unknown!
unknown !
What do we know about UHECRs today?
Who and How is going to address the problem(s)?
Courtesy by C.Lauchaud
Concept ofTUS/TUS2 space free flyer
16x16
PMTs
Fresnel mirror10 rings
Focal distance is 1.5 mField of View is 7.3o
mold production in JINR/DubnaSpace qualified carbon-plastic Fresnel mirror to be produced@ “Luch” (Syzran)
Mirror moldsection
Ring number
Measured vs theory
Measured - theory
[mm]
Orbiting Wide Angle Light-collector (OWL)
Original concept AirWatch (1996)
Improved every year
Two satellites flying in formation
Angular Resolution: 0.2
Energy Resolution: 14%
Aperture: 2X106 km2 ster
Duty Cycle ~12%
Eff. Aperture: 2.3X105 km2 ster
http://owl.gsfc.nasa.gov
EUSO: ISS stationed
optics 2 m diameter
Fresnel lenses 30o FoV 3 years data
taking Now end of Phase A
UHECR
Atmoshpere shower
Air fluoresence
Cerenkov light
Reflection from the Earth
Attenuation in air
Description of telescope
Optique d’EUSO (NASA) : Lentilles de Fresnel
Surface focale: • Structure porteuse FS (France)• électronique ( Italie et France)• PM Multi-anodes ( Japon )
Hamamatsu R5900-M-16/64
Interfaces / Lanceur + Module ISS
Structure porteuse intermédiaire « Alenia » (Italie)
EUSO Frequently Used Software
UNISIM PARIS SLASTS.Bottai E.Plagnol D.NaumovS.Bottai
HYBRID METHODS : FULL MC SIMULATION FOR E>Eth , PARAMETRIZATION FOR E<Eth. Good reproduction of fluctuations with Eth=1017eV.
LPM EFFECT INCLUDED
NEUTRINO SIMULATION OF EHE NEUTRINO INTERACTIONS CC+NC
Single cherenkov scatteringClouds simulation
Common features:3D Geometry and Earth Curvature hadron-air initial interactionProduction of fluorescent and cherenkov lightAtmosphere response
Energy distribution of electrons in shower (impact on both fluorescent and cherenkov light)
Easy configurable atmosphere profiles, attenuation, detector parameters
Neurino CC +NC interactions
ESAF light production engine
D.Naumov, EUSO-SDA-015
h=0 km
h=100 km
An example from LOWTRAN7.1: a vertical transmission from h to
Shower development
Atmosphere response
Fluorescence in air
The Background. The night view of the EARTH
@moonless night we expect 500 photons m-2 ns-1 sr-1, corresponding to 0.3 p.e./s
Clouds
Reflection of the Earth 22 june 2002
EUSO Reconstruction. 1. Incoming directionHired X,Y pixels allows to recover the shower track direction
EUSO Reconstruction. 1. Incoming directionHired X,Y pixels allows to recover the shower track direction
P.Colin, D.Naumov, P.Nedelec, EUSO-SDA-REP-016
EUSO Reconstruction. 1. Incoming directionHired X,Y pixels allows to recover the shower track direction
P.Colin, D.Naumov, P.Nedelec, EUSO-SDA-REP-016 Assuming infinite pixel resoltion
EUSO Reconstruction. 1. Incoming directionHired X,Y pixels allows to recover the shower track direction
EUSO Reconstruction. 2. Altitude of Shower Maximum
Use of Cherenkov echo
Hmax
Xmax
P.Colin, D.Naumov, P.Nedelec, EUSO-SDA-REP-016
Need for an extra device (LIDAR) to detect the reflective surface (cloud) while the Earth relief must be recovered by other meansCherenkov light is drastically suppresed at zenith angle > 70 deg. (important for neutrino showers)
EUSO Reconstruction. 2. Altitude of Shower Maximum
Use only fluorescenceUse of Cherenkov echo
Hmax
Xmax
5km
20 km
Time development of two horizonthal showers. Nmax/Ntot ~ (h)
EUSO Reconstruction. 2. Altitude of Shower Maximum
P.Colin, D.Naumov, P.Nedelec, EUSO-SDA-REP-016
EUSO Reconstruction. 3. Energy
Statistical limit
EUSO Reconstruction. 3. Energy
• Events were generated by Eric Plagnol with the Model Clouds.
- Cloud distribution, types, and population;
• Overall EUSO instrument efficiency 0.07056 is used with SLAST.
• Energy, Height of the shower maximum and/or clouds are blind-fold for EUSO. All of them are autonomously analyzed by the shape methods.
• Two sets of events are provided without identity:
GZK and Super-GZK types.
• Blind-fold testing to reproduce and identify the energy spectrum of two types.
• Existence or absence of the cloud, (and the type of cloud or its height), if any, is not given but derived by the self-diagnosis.
We got quite promising results...People still are not convinced.
Let us play a blind game!
Shower fit by two Gaussian- Wide Fluorescence and narrow Cherenkov
plus Poissonian background noise
Thick-Cloud-hittinghigh Cherenkov peakand close to Nmax
Ground-hittingor low-altitude,thin-cloud hitting
PARIS event (Cloud)E/E (Shape - Cherenkov)= 1.08 x 1020 eV - 1.19 x 1020 eV= 3 - 5% at 7 x 1020 eV.
Hmax = [H (Fluorescence 5.83 km) - H (Cherenkov 4.22 km)] = 1.61kmgives the altitude of clouds Hcloud = 1.6km.
SLAST (no clouds)Hmax = [H (Fluorescence 5.56 km) - H (Cherenkov 5.23 km)] = 0.3km
E/E = 3 - 5% at 7 x 1020 eV
Xmax= 7% (Shape) and 2% (Ch).
Recovery of energy spectra
Conclusions
Whatever the scientific objectives are EUSO is a very interesting and power tool to enter the game! EUSO will collect in 3 years ~few
1000 of events EUSO will be able to separate (to
some extent) p, Fe and neutrino 20-30% error for the energy
measurement is expected